Noncollinear magnets provide essential ingredients for the next generation memory technology. It is a new prospect for the Heusler materials, already well known due to the diverse range of other fundamental characteristics. Here, we present a combined experimental and theoretical study of novel noncollinear tetragonal Mn(2)RhSn Heusler material exhibiting unusually strong canting of its magnetic sublattices. It undergoes a spin-reorientation transition, induced by a temperature change and suppressed by an external magnetic field. Because of the presence of Dzyaloshinskii-Moriya exchange and magnetic anisotropy, Mn(2)RhSn is suggested to be a promising candidate for realizing the Skyrmion state in the Heusler family.

Recently non-collinear magnetic structures have attracted renewed attention due to the novel Hall effects that they display. In earlier work evidence for a non-collinear magnetic structure has been reported for the ferromagnetic Heusler compound Mn 2 RhSn. Using sputtering techniques we have prepared high quality epitaxial thin films of Mn 2 RhSn by high temperature growth on MgO (001) substrates. The films are tetragonally distorted with an easy magnetization axis along the c-axis. Moreover, we find evidence for an anomalous Hall effect whose magnitude increases strongly below the Curie temperature that is near room temperature. Consistent with theoretical calculations of the anomalous Hall conductivity that we have carried out by deriving the Berry curvature from the electronic structure of perfectly ordered Mn 2 RhSn, the sign of the anomalous Hall conductivity is negative, although the measured value is considerably smaller than the calculated value. We attribute this difference to small deviations in stoichiometry and chemical ordering. We also find evidence for a topological Hall resistivity of about 50 nΩ cm, which is ∼5% of the anomalous Hall effect, for temperatures below 100 K. The topological Hall effect signifies the presence of a chiral magnetic structure that evolves from the non-collinear magnetic structure that Mn 2 RhSn is known to exhibit.

The magnetic ground state of the Heusler compound Mn2CoSn was predicted to be nearly halfmetallic ferrimagnetic with a high spin polarization by ab initio electronic structure calculations.Mn2CoSn was synthesized, and the magnetic behavior of the compound was studied using SQUID magnetometry and x-ray magnetic circular dichroism. The experimental values were found to be in fair accordance with the theoretical predictions. The electronic structure and the crystal structure of Mn2CoSn were characterized comprehensively using x-ray powder diffraction, 119 Sn Mössbauer spectroscopy, nuclear magnetic resonance, and hard x-ray photoelectron spectroscopy. LBNL Disclaimer